The invention relates to a method and apparatus for lowering a power window.
In the case of the method for the no-contact reaching of the lower stop position of a power window of a motor vehicle disclosed in German Patent Document DE 196 32 910 C1, it is known to determine system slacks of the window lift mechanism in that, after a closing of the window during the triggering of the drive in the opening direction in a first phase of the adjusting movement, which does not yet result in a displacement of the window, the movement of the driving device is determined and stored as a system slack. When using this system slack, it is suggested that, when a switch-off point is reached during the lowering of the window, for securing this position, the drive is automatically controlled in the lifting direction (closing window) until the system slacks caused by the adjustment of the window in the lowering direction are compensated. As a result, the lift mechanism is braced in the lifting direction and the window is secured in its position against an unintentional lowering, for example, as the result of shocks or vibrations.
In the case of vehicles in which the doors to be opened have a frameless construction, the window engages in a vehicle-body-fixed seal in the closed condition. For safety sealing purposes, for avoiding wind noises and not least for theft protection, such door windows, beyond resting against the seal, are pressed against the seal so that, in the closed condition, the driving mechanism of the window is braced and the window is prestressed. For opening the door, it is required to eliminate the braced condition and, in addition, lower the window by a defined amount in order to disengage the window in this manner from the vehicle-body-fixed seal. This movement, which is also called a short-stroke lowering, is triggered as a rule by operating the door opener.
It is an object of the invention to provide, based on the above-mentioned state of the art, a method for lowering a power window which is improved with respect to the lowering movement of the window.
This object is achieved by preferred embodiments according to the invention, wherein it is suggested to first determine system slacks in an operating device of the window and, when an unlocking of the vehicle, for example, by operating a door lock or by the radio operation of a central locking system, is detected, to eliminate the system slack in the lowering direction of the window by a corresponding control of the operating device. It is advantageously achieved thereby that, during a short-stroke lowering of the window required for opening the door, bracings and system slacks must not first be overcome, but the lowering of the window can start immediately. In the case of an example vehicle, the time saved as the result of the above amounts to 125 ms and contributes to a considerable improvement of the opening action of the door and to a reduction of the stressing of vehicle-body-fixed seals, particularly when the door is opened fast.
Advantageous further developments of preferred embodiments of the invention are described herein and in the claims.
Thus, for determining the system slack, it is suggested that the movement of the window be monitored. When the window is essentially no longer moved, the driving movement of the operating device is monitored and the thus determined driving movement is stored as a system slack. By lowering the window by the system slack determined in such a manner, the window is again brought to the point at which it just rests against the vehicle-body-fixed seal. The monitoring of the movement of the window takes place, for example, according to the method known from German Patent Document DE 196 32 910 C1 (Recognizing the System Slacks As the Result of Bracing).
Another possibility for determining the system slack consists of determining, after a reversal of the moving direction of the window, the driving movement of the operating device from the point in time of the reversal of the moving direction to the recognition of the driving movement of the window and storing the thus obtained value for the driving movement as a system slack. Here also, the monitoring of the movement of the window can take place, for example, according to the method known from German Patent Document DE 196 32 910 C1.
The above-described methods for determining the system slacks can also be used in a manner in which they supplement one another. While, according to the first method, mainly the system slacks resulting from the bracing of the operating device are determined, the second method furnishes the system slacks which result from mechanical tolerances within the operating device. If, when the system slacks are eliminated, only the system slacks determined by means of the first method are taken into account, the window rests without tension on the vehicle-body-fixed seal, but first the slacks of the operating device resulting from the mechanical tolerances must be passed through for a lowering movement. A parallel determination of both system slacks is therefore particularly preferable as well as the elimination of the sum of both system slacks in the lowering direction of the window when the vehicle is unlocked.
If, after the elimination of the system slack, an operation of the door opener is detected, the window is at least partially lowered in order to securely disengage the window from the vehicle-body-fixed seal. After a closing of the door was detected, in which case the door opener must naturally no longer be operated, the window is again completely lifted and braced against the vehicle-body-fixed seal. Subsequently, an elimination of the system slack takes place again in the opening direction of the window. As the result of this approach, it is advantageously ensured that, when the vehicle is unlocked, a further opening of the door, which follows the first opening, takes place without any interlocking of the window with the vehicle-body-fixed seal.
In a supplementary manner, it is suggested to again lift the window completely, that is, to the braced condition, when a speed of the vehicle exceeds a defined limit value. If the speed fails again below this limit value, the system slacks are eliminated again in the above-described manner. This leads to the advantage that, on the one hand, when the vehicle is stopped, the door can be opened without any interlocking of the window with the vehicle-body-fixed seal and, on the other hand, when the vehicle is driving, a secure sealing-off and a suppression of wind noises is ensured by the bracing of the window in the vehicle-body-fixed seal.
As an alternative, it is suggested to not completely lift the window when the defined limit value for the vehicle speed is exceeded, but to only compensate the tolerance-caused system slack plus a portion of the bracing-caused system slack. This can also take place in that the window is first completely lifted and then a portion of the system slack is eliminated in that the operating device is operated by a defined amount in the lowering direction of the window. In this case also, after a falling below the defined limit value of the vehicle speed, the system slack is again completely eliminated. In this approach, when the vehicle is moving, the window is only slightly braced against the vehicle-body-side seal. This bracing is sufficient for ensuring a secure sealing-off and low wind noises. It is also sufficient for securely fixing the window by pressing it against the vehicle-body-fixed seal. In contrast, the stronger bracing applied after the closing-off of the vehicle by the complete lifting of the window represents an optimal protection against theft. As the result of the fact that the complete bracing is now only still applied after the shutting-off of the vehicle, the stressing of the operating device as well as of the vehicle-body-fixed seal is advantageously reduced.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.